2.3 - The digestive organs

2.3 - The diestive organs
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Slide 1: Tekstslide
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In deze les zitten 12 slides, met tekstslides en 1 video.

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2.3 - The diestive organs

Slide 1 - Tekstslide

Oral cavity, pharynx and oesophagus
-digestion begins in oral cavity
-chewing breaks food into small
pieces 
-salivary glands make saliva
-saliva has water, mucus, and enzyme
-Enzyme in saliva breaks down starch
-Swallowing: Food via pharynx to 
oesophagus - uvula and epiglottis closed
-Peristalsis moves food to stomach

Slide 2 - Tekstslide

Why is your stomach rumbling? 
-peristalsis
-muscle activity 
- circular and longitudinal muscles
- mechanical digestion
-stomach constantly moving

-Empty stomach and intestines make a louder sound!

Slide 3 - Tekstslide

In your stomach
Digestive juices are added
-pyloric sphincter
-temporary storage area
-Gastric glands make gastric juices
-Gastric juices are made up of water, hydrochloric acid and enzyme
-Hydrochloric acid kills bacteria
-Gastric juices start to digest proteins


Slide 4 - Tekstslide

Duodenum, Liver, Gall Bladder and Pancreas
2 important liquids added in the first part (the duodenum)
  • Bile made in the liver, stored in the gall bladder
  • Bile emulsifies fats, NO digestion - increases surface area of fats for enzymes to act upon
  • Pancreas makes pancreatic juices - different enzymes to digest proteins, carbohydrates and fats

Slide 5 - Tekstslide

Slide 6 - Tekstslide

small intestine 
  • is very long-> 6 meters
  • contains intestinal glands that make intestinal juice
  • Intestinal juice digests proteins and carbohydrates
  • has many fingerlike projections-> Villi
  • Large total surface area -> making  absorption go faster

Slide 7 - Tekstslide

Characteristics of villi

  • One cell layer thick (thin walls for faster absorption)
  • Good blood supply (fast transport of nutrients to the rest of the body)

Slide 8 - Tekstslide

Appendix
It has no function but can become infected and has to be removed.

Slide 9 - Tekstslide

Large intestine
  • About one and a half meters long
  • Mainly fibre, dead cells, bacteria and water
  • Water absorbed in the blood 
  • No all food can be digested - cellulose from cell walls (plants)
  • waste product becomes more solid-> faeces


Slide 10 - Tekstslide

Where does faeces collect?

  • in the RECTUM
  • when enough is collected the brain signals for elimination
  • Anus - a sphicter (circular muscle) relaxes and rectum empties
  • this is called a bowel movement

Slide 11 - Tekstslide

Slide 12 - Video